The present invention relates to a device and a method for mounting electronic parts on a printed circuit board, and, more particularly to an electronic parts mounting device and a method therefor capable of accurately and quickly providing an angular position for the electronic parts.
There have been electronic parts mounting devices arranged such that an electronic part is sucked to a mounting head in a suction station thereof and is carried to a mounting station thereof at which the electronic part is mounted on a printed circuit board. The position and the attitude of the electronic part thus sucked to the mounting head must be corrected and must have a predetermined angular position (the electronic parts must be turned until they are located in specified mounting angular positions with respect to the printed circuit board) before they are mounted on the printed circuit board.
As disclosed in JP-B-62-12679, a conventional electronic parts mounting device has been arranged in such a manner that the position and the attitude of an electronic part are corrected by rapidly and mechanically holding it by a positioning unit having two pairs of claws at one station. Furthermore, the angular positioning is conducted by turning the positioning unit which is holding the electronic part in a single action by an angular degree of 180.degree. or less. However, the electronic parts mounting device of the type described above encounters a problem in that the electronic part is impacted when it is held by the positioning unit.
As disclosed in JP-A-61-167802, JP-A-61-61499 and JP-A-62-55998, another conventional electronic parts mounting device has been arranged in such a manner that the image of the electronic part sucked to the mounting head is taken by an image pick-up device and the amount of the X and Y directional positional deviations to be corrected and the amount of the angular deviation about a .theta.-axis (the rotational axis of the mounting head) to be corrected are obtained by a visual recognizing device. Then, the mounting head is turned by 180.degree. or less about the .theta.-axis in the angular positioning station by a single action in accordance with the thus obtained amount of the angular deviation to be corrected about the .theta.-axis.
Each of the above-described two conventional structures has the angular positioning mechanism by which the electric part is turned by 180.degree. or less by a single action in one station. Therefore, a Problem arises in that the electronic parts cannot be mounted at high speed. In the latter device, since the mounting nozzle is turned by 180.degree. or less with the electronic part sucked thereto, there is a fear that the position of the electronic Part is changed with respect to the mounting head due to the inertia force of the electronic part over the vacuum suction force if the above described turn is conducted at high speed. Therefore, the angular positioning cannot be conducted at high speed. As a result, an electronic part mounting device has not yet realized a high speed mounting operation.